There is this really cute girl.........please help?

she is awesomely cute....she is in my school but not in the same cl as me.......i only see her sometimes in the corridors of the school.......we have never talked with each other.....i think that she might have seen me in the corridors.... maybe....... she is adorable..... whats should i do???...... i cannot just walk up to her and ask her out.....she does not even know me.........what should i do ????